Method and Device for Making Synthetic Stoppers

ABSTRACT

A method for marking synthetic stoppers comprising: a first step for producing a synthetic stopper, in which, during the process for manufacturing the synthetic stopper, an activator is inserted, the activator being mixed with the synthetic material with which the synthetic stopper is produced, and a second step for marking the synthetic stopper, in which a light beam strikes the synthetic stopper and is absorbed, generating heat, which generates a thermal reaction on the activator, and the thermal reaction degrades the activator proximate to the surface of the synthetic stopper, so that the activator assumes a different color in contrast with the color of the surface of the synthetic stopper, so as to make the intended marking visible.

TECHNICAL FIELD

The present invention relates to a method for marking synthetic stoppers, to a device for providing said method, and to a synthetic stopper.

BACKGROUND ART

More specifically, the present invention relates to a method for marking synthetic stoppers, to a device for providing such method, and to a synthetic stopper, particularly but not exclusively adapted to be used to mark cylindrical and mushroom-shaped synthetic stoppers in the food sector and in particular in the wine-making sector in bottling.

In the food sector, and particularly in the wine-making sector in wine bottling, it is known and usual to close containers and/or bottles with cork stoppers and to mark such stoppers with identification codes and/or with the name and/or trademark of the maker and/or with other information deemed to be important.

It is also known that in recent times there is an increasing use of synthetic stoppers made of materials suitable for contact with food, such as for example polyethylene, EVA, elastomers (SEBS, SBS, SEPS, etc), polypropylene (homopolymer or copolymer).

These synthetic stoppers are marked by methods which provide for:

-   -   pretreating the stoppers with a corona or plasma treatment;     -   marking the stopper by applying directly ink or papers and/or         plastic films onto which ink is applied; and     -   fixing the ink by means of ultraviolet rays.

Although the stoppers thus marked are used and appreciated, they are not devoid of drawbacks, one of which is the lack of food compatibility of the ink. A second drawback is the fact that the ink does not adhere stably to the surface of the stopper and, by detaching, remains on the neck of the container or bottle or, by dissolving, is dispersed in the contents or in the wine.

DISCLOSURE OF THE INVENTION

Therefore, the aim of the present invention is to provide a method for marking synthetic stoppers, a device for carrying out the method and a synthetic stopper which eliminate the drawbacks mentioned in relation to the background art.

According to the present invention, this aim and other objects, which will become apparent from the following description, are achieved by a method for marking synthetic stoppers generally defined in claim 1, by a device for providing said method, generally defined in claim 10, and by a synthetic stopper generally defined in claim 14.

BRIEF DESCRIPTION OF THE DRAWINGS

The method for marking synthetic stoppers and the constructive and functional characteristics of the device for providing said method and the synthetic stopper according to the present invention can be understood more clearly from the following description, which refers to the figures of the accompanying drawings, which illustrate an embodiment given merely by way of non-limiting example, wherein:

FIG. 1 is a block diagram of the method for marking synthetic stoppers according to the present invention;

FIGS. 2 a, 2 b and 2 c show a diagram of a step of the method for marking synthetic stoppers of FIG. 1; and

FIG. 3 is a schematic view of the device for providing the step of FIG. 2 of the method for marking synthetic stoppers of FIG. 1.

WAYS OF CARRYING OUT THE INVENTION

With reference to the figures, the method for marking synthetic stoppers according to the present invention is generally designated by the reference numeral 1.

The method for marking synthetic stoppers 1 comprises a first step 2 for producing a synthetic stopper 10, in which, during the process for producing said synthetic stopper, which is per se known and therefore not described further, an activator is inserted by mixing it with the synthetic material with which said synthetic stopper 10 is produced.

The material with which the synthetic stopper 10 is produced is selected among non-toxic materials suitable for use in the food sector, such as for example polyethylene, polypropylene, EVA, elastomers (SEBS, SBS, SEPS, or other suitable elastomers) and preferably a compound of polyethylene/EVA, polyethylene/SEBS, polyethylene/EVA/SEBS.

The method for marking synthetic stoppers 1 comprises a second step 4 for marking the synthetic stopper 10, in which a light beam strikes the synthetic stopper (FIG. 2 a) and is absorbed, generating heat (FIG. 2 b). The heat thus produced generates a thermal reaction on the pigment which causes said pigment, proximate to the surface of the synthetic stopper 10, to degrade (FIG. 2 c), assuming a different color in contrast with the color of the surface of the synthetic stopper, so as to make the intended marking visible.

The light beam used for marking is obtained by using a light source which emits said light beam with a wavelength ranging from 200 to 1064 nm, preferably 532 nm, a power ranging from 2 to 30 W, and preferably from 3 to 10 W, and a frequency ranging from 10 to 100 kHz, and preferably from 20 to 65 kHz.

Advantageously, the light source is selected among double- or triple-frequency excimer lasers known as YAG lasers, or CO₂ pulse lasers, or ultraviolet lasers.

The activator or pigment used in the production of the synthetic stopper is selected as a function of the light source or laser used. For CO₂ lasers, said pigment is selected among kaolins, chalks, alumina, phyllosilicates and mica; for YAG lasers, said pigment can be antimony oxide III; and for both CO₂ lasers and YAG lasers, said pigment is selected among metallic pigments, pearl luster pigments, carbon black and mica coated with metallic oxides.

Preferably, pigments based on oxides or dioxides of metals, such as for example titanium dioxide, iron oxide, chromium oxide, nickel titanate, ultramarine blu and other metal oxides or bioxides that can be used in pigments, or mineral charges such as calcium carbonate, talc and silica are selected among the pigments in order to obtain optimum marking.

With reference to FIG. 3, the reference numeral 20 generally designates a device for providing the second step 4 for marking the synthetic stopper 10. Such device 20 comprises a hopper, into which the stoppers 10 are loaded, the hopper being provided with a vibrating unit which positions them and sorts them on a conveyor belt. The conveyor belt advances at a preset speed, which is adjusted by a step motor. At the end of the conveyor belt, the device comprises a handling unit provided with at least one grip hand 30 and a laser unit as defined earlier. Preferably, the handling unit comprises two grip hands 30. Advantageously, the grip hands 30 are capable of picking up four synthetic stoppers 10 for each picking action, in order to arrange them exactly in the work area of the laser unit. Advantageously, moreover, said grip hands 30 can rotate about themselves through a chosen angle, preferably 180°, in order to produce markings or marking elements which are angled to each other.

In operation, one grip hand 30 picks up four synthetic stoppers 10 from the conveyor belt and arranges them in the work area of the laser. While the grip hand 30 keeps the first four synthetic stoppers 10 positioned in the laser work area, the other grip hand 30 is arranged on the conveyor belt in order to pick up the next four synthetic stoppers 10. When the marking operation has ended, the corresponding grip hand 30 in the work area is opened and the synthetic stoppers 10 that have already been marked fall into a chute, which conveys them to a collection container.

The method for marking synthetic stoppers 1 according to the present invention has proved to be particularly effective, allowing to mark a synthetic stopper 10 in a time ranging from a minimum of a few tenths of a second up to three seconds, depending on what has to be marked on the stopper, thus ensuring an hourly productivity which ranges from a minimum of 500 up to a maximum of 3500 synthetic stoppers 10.

Advantageously, the method for marking synthetic stoppers 1 according to the present invention has proved to be particularly effective in ensuring that the marking is completely neutral. Also advantageously, the method for marking synthetic stoppers 1, allows, by means of a computer connected to the laser unit, to identify each individual synthetic stopper 10 by numbering it, creating a progressively numbered stopper; in this way, a manufacturer, if necessary, can code the stoppers and consequently customize the containers or bottles, as in the case of wine-making, so as to also avoid any forgeries. It is also possible to mark the synthetic stopper with a bar code, in addition to the maker's trademark and name.

As can be appreciated from the above description, the method for marking synthetic stoppers 1 according to the present invention has proved to be particularly functional, versatile and easy to provide, allowing to achieve the aim and overcome the drawbacks mentioned in relation to the background art.

Although the present invention has been described with reference to one of its embodiments, given merely by way of non-limiting example, it is evident that persons skilled in the art may apply many variations and modifications in the light of the description given above. Therefore, the present invention intends to encompass all modifications and variations which fall within the protective scope of the appended claims.

The disclosures in Italian Patent Application No. MI2004A002454 from which this application claims priority are incorporated herein by reference. 

What is claimed is: 1-15. (canceled)
 16. A method for marking synthetic stoppers, comprising a first step for producing a synthetic stopper, in which, during the process for manufacturing said synthetic stopper, an activator is inserted, said activator being mixed with the synthetic material with which said synthetic stopper is produced, and a second step for marking the synthetic stopper, in which a light beam strikes said synthetic stopper and is absorbed, generating heat, said heat generating a thermal reaction on said activator, said thermal reaction degrading said activator proximate to the surface of the synthetic stopper, so that said activator assumes a different color in contrast with the color of said surface of said synthetic stopper, so as to make the intended marking visible.
 17. The method for marking synthetic stoppers according to claim 16, wherein the synthetic stopper is made of polyethylene, polypropylene, EVA, elastomers (SEBS, SBS, SEPS, or other suitable elastomers) and preferably made of a compound of polyethylene/EVA, polyethylene/SEBS, polyethylene/EVA/SEBS.
 18. The method for marking synthetic stoppers according to claim 16, wherein the light beam is obtained from a light source which emits said light beam with a wavelength ranging from 200 to 1064 nm, a power ranging from 2 to 30 W, and a frequency ranging from 10 to 100 kHz.
 19. The method for marking synthetic stoppers according to claim 18, wherein the light beam is obtained from a light source which emits said light beam with a wavelength of 532 nm, a power from 3 to 10 W, and a frequency from 20 to 65 kHz.
 20. The method for marking synthetic stoppers according to claim 18, wherein the light source is a double- or triple-frequency excimer laser or a YAG laser or a CO₂ pulse laser.
 21. The method for marking synthetic stoppers according to claim 16, wherein the activator is a pigment.
 22. The method for marking synthetic stoppers according to claim 21, wherein the pigment is selected among kaolins, chalks, alumina, phyllosilicates, mica, antimony oxide III, metallic pigments, pearl luster pigments, carbon black and mica coated with metallic oxides.
 23. The method for marking synthetic stoppers according to claim 22, wherein the pigment is selected among pigments based on oxides or dioxides of metals.
 24. The method for marking synthetic stoppers according to claim 23, wherein said pigments are titanium dioxide, iron oxide, chromium oxide, nickel titanate.
 25. A device for performing the method of claim 16, comprising a hopper provided with a vibration unit, a conveyor belt, which advances at a preset speed adjusted by a step motor, a handling unit provided with at least one grip hand, and a laser unit for performing the second step for marking the synthetic stopper.
 26. The device according to claim 25, wherein the handling unit comprises two grip hands.
 27. The device according to claim 26, wherein the grip hand is capable of picking up four synthetic stoppers at each pick-up action.
 28. The device according to claim 27, wherein the grip hand is capable of rotating about itself through a selected angle.
 29. A synthetic stopper obtained with the method for marking synthetic stoppers according to claim
 16. 30. The synthetic stopper according to claim 29, wherein the second step for marking said synthetic stopper is performed by means of the device according to claim
 25. 